Whole exome sequencing of germline DNA of individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced lung adenocarcinoma (LUAD) according to KRAS status.

1540 Background: Individual susceptibility to carcinogens may depend on the genetic background. We characterized the constitutional exome of individuals presenting extreme phenotypes of high sensitivity and resistance to develop tobacco induced LUAD, correlating the results to KRAS status. Methods: From an identification cohort (n=3,631) we selected 100 caucasian heavy smokers that either developed LUAD at early age (cancer cohort, n=50) or did not develop LUAD or other tumors at advanced age (cancer free cohort, n=50). We sequenced their germline DNA with the Agilent Human Exome Capture v5 (21,522 genes, 357,999 exons). Using logistic regression we selected the most significant variants between both cohorts and correlated them with KRAS mutation status of LUAD patients. Results: mean ages for the cancer and cancer free cohorts were 50 (range 34-55) and 78 years (72-90). Mean tobacco consumptions were 44 (range 6-72) and 55 pack-years (20-124). Median coverage was 96% at >10X; median depth was 97X. Table shows the most significant variants. rs7240666 ( ALPK2) achieved top significance (p=8.14x10-5, OR 0.18). rs78898229 ( ANKRD36C) and rs74866537 ( PTPN4) were predominantly represented in patients with KRAS+ tumors, OR: 16 (3.3-78) and 11.9 (3.3-43); and rs12426243 (CCDC41) in KRAS- tumors (OR: 13 (3-53). Conclusions: Our study characterizes for the first time the genotype of individuals presenting extreme phenotypes of high and low risk to develop tobacco-induced LUAD according to KRAS status. Our results warrants further study to assess their value to screen these clinically relevant phenotypes; and to identify mechanisms of high susceptibility and resistance to carcinogens. [Table: see text]